Object detection and scan

ABSTRACT

In certain embodiments, a method includes selecting, for a touch sensor including a first number of electrodes and a second number of electrodes, a first set of the first number of electrodes and a second set of the second number of electrodes. The first number of electrodes has a first orientation and the second number of electrodes has a second orientation. The second orientation being different from the first orientation. An overlap area is formed by an overlap of the first set and second set. The method also includes applying, during a first time period, a signal including a first pre-determined voltage to the first set and the second set such that, during the first time period, the overlap area has a first signal state; and applying, during a second time period, the signal to the first set and a second pre-determined voltage to the second set.

RELATED APPLICATIONS

This application claims the benefit, under 35 U.S.C. §119(e), of U.S.Provisional Patent Application Ser. No. 62/103,500, filed Jan. 14, 2015,the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure generally relates to touch sensors.

BACKGROUND

A touch sensor detects the presence and position of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of a touch sensor array overlaid on a displayscreen, for example. A touch sensor may be attached to or provided aspart of a number of different devices, such as, for example, a desktopcomputer, laptop computer, tablet computer, personal digital assistant(PDA), smartphone, satellite navigation device, portable media player,portable game console, kiosk computer, point-of-sale device. To furtherillustrate, one example provides that a control panel of a household orother appliance includes a touch sensor.

There are a number of different types of touch sensors, such as (forexample) resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. When an object touches the surface oftouch sensor array, a change in capacitance occurs within the touchscreen at the position of the touch or proximity. A touch sensorcontroller processes the change in capacitance to determine its positionon the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor array with an exampletouch-sensor controller in accordance with an embodiment.

FIGS. 2A-B illustrate an example self-capacitance measurement inaccordance with an embodiment.

FIG. 3 illustrates example components of an active stylus in accordancewith an embodiment.

FIG. 4 illustrates an example stylus input to a device in accordancewith an embodiment.

FIG. 5 illustrates an example pattern for applying voltages during afirst time period in accordance with an embodiment.

FIG. 6 illustrates an example pattern for applying voltages during asecond time period in accordance with an embodiment.

FIG. 7 illustrates an example pattern for applying voltages during athird time period in accordance with an embodiment.

FIG. 8 illustrates an example pattern for applying voltages during afourth time period in accordance with an embodiment.

FIG. 9 illustrates an example touch exclusion bias pattern covering anarea of a touch input in accordance with an embodiment.

FIG. 10 illustrates an example touch exclusion bias pattern covering aportion of an area of a touch input in accordance with an embodiment.

FIG. 11 illustrates an example touch exclusion bias pattern withelectrodes along the horizontal orientation in accordance with anembodiment.

FIG. 12 illustrates an example touch exclusion bias pattern withelectrodes along the vertical orientation in accordance with anembodiment.

FIG. 13 illustrates an example touch exclusion bias pattern for multipletouch inputs in accordance with an embodiment.

FIG. 14A illustrates an example synchronization bias patterns having anoverlap area around an object in accordance with an embodiment.

FIG. 14B illustrates an example synchronization bias patterns having anoverlap area and guard band around an object in accordance with anembodiment.

FIG. 15 illustrates an example synchronization bias pattern having oneor more overlap areas along one or more edges of the touch sensor inaccordance with an embodiment.

FIG. 16A illustrates an example method for detecting an object inaccordance with an embodiment.

FIG. 16B illustrates an example method for detecting an object throughsearch patterns in accordance with an embodiment.

FIG. 17 illustrates an example method for detecting an object throughtouch area exclusion in accordance with an embodiment.

FIG. 18 illustrates an example method for synchronizing a stylus with adevice in accordance with an embodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor array with an exampletouch-sensor controller in accordance with an embodiment. Touch sensor10 and touch-sensor controller 12 detect the presence and position of atouch or the proximity of an object within a touch-sensitive area oftouch sensor array 10. Touch sensor array 10 includes one or moretouch-sensitive areas. Touch sensor array 10 includes an array ofelectrodes disposed on one or more substrates, which is made of adielectric material. Herein, reference to a touch sensor arrayencompasses both the electrodes of touch sensor 10 and the substrate(s)that they are disposed on.

An electrode is an area of conductive material forming a shape, such asfor example a disc, square, rectangle, thin line, other suitable shape,or suitable combination of these. One or more cuts in one or more layersof conductive material (at least in part) creates the shape of anelectrode, and the area of the shape may (at least in part) be boundedby those cuts. In one embodiment, the conductive material of anelectrode occupies approximately 100% of the area of its shape. Forexample, an electrode is made of indium tin oxide (ITO) and the ITO ofthe electrode occupies approximately 100% of the area of its shape(sometimes referred to as 100% fill). In one embodiment, the conductivematerial of an electrode occupies substantially less than 100% of thearea of its shape. For example, an electrode is made of fine lines ofmetal or other conductive material (FLM), such as for example copper,silver, or a copper- or silver-based material, and the fine lines ofconductive material occupies approximately 5% of the area of its shapein a hatched, mesh, or other suitable pattern. Although this disclosuredescribes or illustrates particular electrodes made of particularconductive material forming particular shapes with particular fillpercentages having particular patterns, it is noted that the presenttechnology is not limited to these example patterns, and that otherelectrode patterns may be implemented.

The shapes of the electrodes (or other elements) of a touch sensor 10constitutes, in whole or in part, one or more macro-features of touchsensor 10. One or more characteristics of the implementation of thoseshapes (such as, for example, the conductive materials, fills, orpatterns within the shapes) constitutes in whole or in part one or moremicro-features of touch sensor 10. One or more macro-features of a touchsensor 10 determines one or more characteristics of its functionality,and one or more micro-features of touch sensor 10 determines one or moreoptical features of touch sensor 10, such as transmittance, refraction,or reflection.

A mechanical stack contains the substrate (or multiple substrates) andthe conductive material forming the electrodes of touch sensor array 10.For example, the mechanical stack includes a first layer of opticallyclear adhesive (OCA) beneath a cover panel. The cover panel is clear andmade of a resilient material suitable for repeated touching, such as forexample glass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA is disposed between the cover panel andthe substrate with the conductive material forming the electrodes. Themechanical stack includes a second layer of OCA and a dielectric layer(which is made of PET or another suitable material, similar to thesubstrate with the conductive material forming the electrodes). As analternative, a thin coating of a dielectric material is applied insteadof the second layer of OCA and the dielectric layer. The second layer ofOCA is disposed between the substrate with the conductive materialmaking up the electrodes and the dielectric layer, and the dielectriclayer is disposed between the second layer of OCA and an air gap to adisplay of a device including touch sensor array 10 and touch-sensorcontroller 12. For example, the cover panel has a thickness ofapproximately 1 millimeter (mm); the first layer of OCA has a thicknessof approximately 0.05 mm; the substrate with the conductive materialforming the electrodes has a thickness of approximately 0.05 mm; thesecond layer of OCA has a thickness of approximately 0.05 mm; and thedielectric layer has a thickness of approximately 0.05 mm. Although thisdisclosure describes a particular mechanical stack with a particularnumber of particular layers made of particular materials and havingparticular thicknesses, it is noted that the present technology is notlimited to these example embodiments, and that other configurations maybe implemented. For example, in one embodiment, a layer of adhesive ordielectric replaces the dielectric layer, second layer of OCA, and airgap described above, with there being no air gap in the display.

One or more portions of the substrate of touch sensor array 10 is madeof polyethylene terephthalate (PET) or other suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In one embodiment, theelectrodes in touch sensor array 10 is made of ITO in whole or in part.In one embodiment, the electrodes in touch sensor array 10 is made offine lines of metal or other conductive material. For example, one ormore portions of the conductive material is copper or copper-based andhave a thickness of approximately 5 microns (μm) or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material is silver or silver-based and similarly have athickness of approximately 5 μm or less and a width of approximately 10μm or less. It is noted that the present technology is not limited tothese example electrodes.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 includes an array ofdrive and sense electrodes forming an array of capacitive nodes. A driveelectrode and a sense electrode forms a capacitive node. The drive andsense electrodes forming the capacitive node comes near each other, butdoes not make electrical contact with each other. Instead, the drive andsense electrodes is capacitively coupled to each other across a spacebetween them. A pulsed or alternating voltage applied to the driveelectrode (by touch-sensor controller 12) induces a charge on the senseelectrode, and the amount of charge induced is susceptible to externalinfluence (such as a touch or the proximity of an object). When anobject touches or comes within proximity of the capacitive node, achange in capacitance occurs at the capacitive node and touch-sensorcontroller 12 measures the change in capacitance. By measuring changesin capacitance throughout the array, touch-sensor controller 12determines the position of the touch or proximity within touch-sensitivearea 54(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 includes an arrayof electrodes of a single type that each forms a capacitive node. Whenan object touches or comes within proximity of the capacitive node, achange in self-capacitance occurs at the capacitive node andtouch-sensor controller 12 measures the change in capacitance, forexample, as a change in the amount of charge implemented to raise thevoltage at the capacitive node by a pre-determined amount. As with amutual-capacitance implementation, by measuring changes in capacitancethroughout the array, touch-sensor controller 12 determines the positionof the touch or proximity within touch-sensitive area 54(s) of touchsensor 10. This disclosure contemplates any suitable form of capacitivetouch sensing.

In one embodiment, one or more drive electrodes form a drive linerunning horizontally or vertically or in any suitable orientation.Similarly, one or more sense electrodes form a sense line runninghorizontally or vertically or in any suitable orientation. In oneembodiment, drive lines run substantially perpendicular to the senselines. Herein, reference to a drive line encompasses one or more driveelectrodes making up the drive line, and vice versa. Similarly,reference to a sense line encompasses one or more sense electrodesmaking up the sense line, and vice versa.

Touch sensor 10 has drive and sense electrodes disposed in a pattern onone side of a single substrate. In such a configuration, a pair of driveand sense electrodes capacitively coupled to each other across a spacebetween them forms a capacitive node. For a self-capacitanceimplementation, electrodes of a single type are disposed in a pattern ona single substrate. In addition or as an alternative to having drive andsense electrodes disposed in a pattern on one side of a singlesubstrate, touch sensor 10 has drive electrodes disposed in a pattern onone side of a substrate and sense electrodes disposed in a pattern onanother side of the substrate. Moreover, touch sensor 10 has driveelectrodes disposed in a pattern on one side of one substrate and senseelectrodes disposed in a pattern on one side of another substrate. Insuch configurations, an intersection of a drive electrode and a senseelectrode forms a capacitive node. Such an intersection is a positionwhere the drive electrode and the sense electrode “cross” or comenearest each other in their respective planes. The drive and senseelectrodes do not make electrical contact with each other—instead theyare capacitively coupled to each other across a dielectric at theintersection. Although this disclosure describes a number of exampleelectrodes, it is noted that the present technology is not limited tothese example electrodes, and that other electrodes may be implemented.Additionally, although this disclosure describes a number of exampleembodiments that include particular configurations of particularelectrodes forming particular nodes, it is noted that the presenttechnology is not limited to these example embodiments, and that otherconfigurations may be implemented. Additionally, although thisdisclosure describes a number of example embodiments that includeparticular configurations of particular electrodes forming particularnodes, it is noted that the present technology is not limited to theseexample embodiments, and that other configurations may be implemented.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 indicates a touch or proximity input at the position ofthe capacitive node. Touch-sensor controller 12 detects and processesthe change in capacitance to determine the presence and position of thetouch or proximity input. Touch-sensor controller 12 then communicatesinformation about the touch or proximity input to one or more othercomponents (such as one or more central processing units (CPUs)) of adevice that includes touch sensor 10 and touch-sensor controller 12,which responds to the touch or proximity input by initiating a functionof the device (or an application running on the device). Although thisdisclosure describes a particular touch-sensor controller havingparticular functionality with respect to a particular device and aparticular touch sensor, it is noted that the present technology is notlimited to these example controllers.

Touch-sensor controller 12 is one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices or arrays, application-specific ICs (ASICs).In one embodiment, touch-sensor controller 12 comprises analogcircuitry, digital logic, and digital non-volatile memory. In oneembodiment, touch-sensor controller 12 is disposed on a flexible printedcircuit (FPC) bonded to the substrate of touch sensor 10, as describedbelow. The FPC is active or passive. In one embodiment, multipletouch-sensor controllers 12 are disposed on the FPC. Touch-sensorcontroller 12 includes a processor unit, a drive unit, a sense unit, anda storage unit. The drive unit supplies drive signals to the driveelectrodes of touch sensor 10. The sense unit senses charge at thecapacitive nodes of touch sensor 10 and provide measurement signals tothe processor unit representing capacitances at the capacitive nodes.The processor unit controls the supply of drive signals to the driveelectrodes by the drive unit and process measurement signals from thesense unit to detect and process the presence and position of a touch orproximity input within touch-sensitive area 54(s) of touch sensor 10.The processor unit also tracks changes in the position of a touch orproximity input within touch-sensitive area 54(s) of touch sensor 10.The storage unit stores programming for execution by the processor unit,including programming for controlling the drive unit to supply drivesignals to the drive electrodes, programming for processing measurementsignals from the sense unit, and other suitable programming. Althoughthis disclosure describes a particular touch-sensor controller having aparticular implementation with particular components, it is noted thatthe present technology is not limited to these example controllers.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 couples the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 extend into or around (e.g., atthe edges of) touch-sensitive area 54(s) of touch sensor 10. Particulartracks 14 provide drive connections for coupling touch-sensor controller12 to drive electrodes of touch sensor 10, through which the drive unitof touch-sensor controller 12 supplies drive signals to the driveelectrodes. Other tracks 14 provide sense connections for couplingtouch-sensor controller 12 to sense electrodes of touch sensor 10,through which the sense unit of touch-sensor controller 12 senses chargeat the capacitive nodes of touch sensor 10. Tracks 14 are made of finelines of metal or other conductive material. For example, the conductivematerial of tracks 14 is copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 is silver or silver-based and have a width ofapproximately 100 μm or less. In one embodiment, tracks 14 are made ofITO in whole or in part in addition or as an alternative to the finelines of metal or other conductive material. Although this disclosuredescribes particular tracks made of particular materials with particularwidths, it is noted that the present technology is not limited to theseexample tracks. In addition to tracks 14, touch sensor 10 includes oneor more ground lines terminating at a ground connector (which is aconnection pad 16) at an edge of the substrate of touch sensor 10(similar to tracks 14).

Connection pads 16 are located along one or more edges of the substrate,outside touch-sensitive area 54(s) of touch sensor 10. As describedabove, touch-sensor controller 12 is on an FPC. Connection pads 16 aremade of the same material as tracks 14 and are bonded to the FPC usingan anisotropic conductive film (ACF). Connection 18 includes conductivelines on the FPC coupling touch-sensor controller 12 to connection pads16, in turn coupling touch-sensor controller 12 to tracks 14 and to thedrive or sense electrodes of touch sensor 10. In another embodiment,connection pads 16 are connected to an electro-mechanical connector(such as a zero insertion force wire-to-board connector); in thisembodiment, connection 18 need not include an FPC. It is noted that thepresent technology is not limited to these example connections.

FIGS. 2A-B illustrate an example self-capacitance measurement inaccordance with an embodiment. In the example of FIG. 2A, an electrode24 of touch sensor 10 is coupled to a measurement circuit 20. Asdescribed below, electrode 24 forms a capacitance to ground that isdistributed in free space. In one embodiment, the capacitance to groundincludes multiple elements, such as for example, capacitance of thetracks in the silicon, tracks on the printed circuit board (PCB),electrodes 24 made of conductive material (ITO, copper mesh, etc.), oran object 22 providing an input to electrodes 24. For example, object 22is part of a human body, e.g., finger or palm, or a stylus. Electrode 24has capacitive coupling to ground through the surrounding objects thatare galvanically or capacitively connected to ground. As describedabove, measurement circuit 20 of touch-sensor controller 12 transmits adrive signal and senses a signal indicative of a touch or proximityinput from object 22, such as for example a finger, through electrode24. In one embodiment, measurement circuit 20 of touch-sensor controller12 generates the drive signal transmitted by electrode 24 and senses thecapacitance to ground. The capacitance of the surrounding materialincludes at least in part, the capacitance between electrode 24 andground with object 22 providing the touch or proximity input. Forexample, the capacitance provided by object 22 providing the touch orproximity input adds 5-10% of the capacitance sensed by electrode 24.

In the example of FIG. 2B, the signal transmitted by electrode 24generates an electric field that emanates from electrode 24 to a signalground of touch sensor 10. The signal ground is galvanically orcapacitively coupled to ground. The presence of an object 22, such asfor example finger, affects the electric field and in turn the amount ofcharge sensed at electrode 24 by measurement circuit 20. As object 22approaches electrode 24, the capacitance between electrode 24 and grounddetected by measurement circuit 20 increases. In one embodiment, theincrease of the capacitance between electrode 24 and ground is measuredby measurement circuit 20 as a decrease of voltage at the capacitancebetween electrode 24 and ground. In one embodiment, measurement circuit20 is alternately toggled between the drive and sense electrodes of atouch sensor in a mutual capacitance configuration. Although thisdisclosure describes the measurement circuit being integrated with atouch-sensor controller, it is noted that the present technology is notlimited to these embodiments.

FIG. 3 illustrates example components of an active stylus in accordancewith an embodiment. Active stylus 30 includes one or more components,such as a controller 40, sensors 42, memory 44, or power source 48. Inone embodiment, one or more components is configured to provide forinteraction between active stylus 30 and a user or between a device anda user. In other one embodiment, one or more internal components, inconjunction with one or more external components described above, isconfigured to provide interaction between active stylus 30 and a user orbetween a device and a user. For example, interactions may includecommunication between active stylus 30 and a device, enabling oraltering functionality of active stylus 30 or a device, or providingfeedback to or accepting input from one or more users. As anotherexample, active stylus 30 may communicate over an energy datatransmission or modulation link, such as, for example, through a radiofrequency (RF) communication link. In this case, active stylus 30includes a RF device for transmitting data over the RF link.

Controller 40 is a microcontroller or any other type of processorsuitable for controlling the operation of active stylus 30. Controller40 is one or more ICs—such as, for example, general-purposemicroprocessors, microcontrollers, PLDs, PLAs, or ASICs. Controller 40includes a processor unit, a drive unit, a sense unit, and a storageunit. The drive unit supplies signals to electrodes of tip 26 throughcenter shaft 41. The drive unit also supplies signals to control ordrive sensors 42 or one or more external components of active stylus 30.In one embodiment, the drive unit of active stylus 30 is configured tocontinuously transmit a signal that is detected by electrodes of touchsensor 10. For example, the drive unit of active stylus 30 may include avoltage pump, an oscillator, or a switch, such that the voltage pumpgenerates a voltage signal, the oscillator generates a waveform such asa square wave or a sine wave, or the switch toggles the potential of tip26 between zero voltage and a maximum voltage. The drive unit of activestylus 30 transmits a signal, such as a square wave or sine wave, thatis sensed by the electrodes.

The sense unit senses signals received by electrodes of tip 26 throughcenter shaft 41 and provide measurement signals to the processor unitrepresenting input from a device. The sense unit also senses signalsgenerated by sensors 42 or one or more external components and providemeasurement signals to the processor unit representing input from auser. The processor unit controls the supply of signals to theelectrodes of tip 26 and process measurement signals from the sense unitto detect and process input from the device. The processor unit alsoprocesses measurement signals from sensors 42 or one or more externalcomponents. The storage unit stores programming for execution by theprocessor unit, including programming for controlling the drive unit tosupply signals to the electrodes of tip 26, programming for processingmeasurement signals from the sense unit corresponding to input from thedevice, programming for processing measurement signals from sensors 42or external components to initiate a pre-determined function or gestureto be performed by active stylus 30 or the device, and other suitableprogramming. For example, programming executed by controller 40electronically filters signals received from the sense unit. Althoughthis disclosure describes a particular controller 40 having a particularimplementation with particular components, it is noted that the presenttechnology is not limited to these example components.

In one embodiment, active stylus 30 includes one or more sensors 42,such as touch sensors, gyroscopes, accelerometers, contact sensors, orany other type of sensor that detects or measures data about theenvironment in which active stylus 30 operates. Sensors 42 detect andmeasure one or more characteristic of active stylus 30, such asacceleration or movement, orientation, contact, pressure on outer body46, force on tip 26, vibration, or any other suitable characteristic ofactive stylus 30. For example, sensors 42 is implemented mechanically,electronically, or capacitively. As described above, data detected ormeasured by sensors 42 communicated to controller 40 initiates apre-determined function or gesture to be performed by active stylus 30or the device. In one embodiment, data detected or received by sensors42 is stored in memory 44. Memory 44 is any form of memory suitable forstoring data in active stylus 30. In one embodiment, controller 40accesses data stored in memory 44. For example, memory 44 storesprogramming for execution by the processor unit of controller 40. Asanother example, data measured by sensors 42 is processed by controller40 and stored in memory 44.

Power source 48 is any type of stored-energy source, includingelectrical or chemical-energy sources, suitable for powering theoperation of active stylus 30. In one embodiment, power source 48 ischarged with energy from a user or device. For example, power source 48is a rechargeable battery that is charged by motion induced on activestylus 30. In other one embodiment, power source 48 of active stylus 30provides power to or receive power from the device or other externalpower source. For example, power is inductively transferred betweenpower source 48 and a power source of the device or other external powersource, such as a wireless power transmitter. Power source 48 is alsopowered by a wired connection through an applicable port coupled to asuitable power source.

FIG. 4 illustrates an example stylus input to a device. Device 50 mayhave a display (not shown) and a touch sensor 10 with a touch-sensitivearea 54 in accordance with an embodiment. Device 50 display is a liquidcrystal display (LCD), a LED display, a LED-backlight LCD, anactive-matrix organic LED (AMOLED), or other suitable display and isvisible though a cover panel and substrate (and the drive and senseelectrodes of touch sensor 10 disposed on it) of device 50. Althoughthis disclosure describes a particular device display and particulardisplay types, it is noted that the present technology is not limited tothese example embodiments, and that other configurations may beimplemented.

Device 50 electronics may provide the functionality of device 50. Forexample, device 50 electronics includes circuitry or other electronicsfor wireless communication to or from device 50, execute programming ondevice 50, generating graphical or other user interfaces (UIs) fordevice 50 display to display to a user, managing power to device 50 froma battery or other power source, taking still pictures, recording video,other suitable functionality, or any suitable combination of these.Although this disclosure describes particular device electronicsproviding particular functionality of a particular device, it is notedthat the present technology is not limited to these examplefunctionalities.

Touch-sensor controller 12 of device 50 operates in one or more modes.In one embodiment, with respect to object interaction, touch-sensorcontroller 12 operates in at least the following two modes: “object notdetected” and “object detected.” In the “object not detected” mode,touch-sensor controller 12 interleaves self-capacitance, mutualcapacitance, and active stylus 30 “not detected” mode measurements todetect touch or proximity inputs, including, for example, the presenceof active stylus 30 during the same measurement cycle. Each of thesetypes of measurements is used to detect certain types of inputsperformed on or above touch-sensitive area 54. For example, touch-sensorcontroller 12 uses self-capacitance measurements to detect certain touchor proximity inputs. In one embodiment, touch-sensor controller 12 usesself-capacitance measurements to detect single-finger touches or largearea palm touches. As another example, touch-sensor controller 12 usesmutual capacitance measurements to detect certain touch or proximityinputs. In one embodiment, touch-sensor controller 12 uses mutualcapacitance measurements to detect multiple small touches or multi-touchinput. As described below, touch-sensor controller 12 makes the “objectnot detected” measurements using a modified self-capacitance measurementconfigured to provide position data of active stylus 30 abovetouch-sensitive area 54; however, it is noted that the presenttechnology is not limited to these example techniques, and that othertechniques may be implemented.

Although particular measurement types are described as being used todetect particular types of touch or proximity inputs, it is noted thatthe present technology is not limited to these example inputs. Forexample, the present disclosure contemplates using any of theabove-described measurement types to detect any suitable type of touchor proximity input. As used herein, the terms “touch” and “proximity”are used interchangeably to refer to both physical touches (e.g., oftouch sensor 10 or a cover layer overlaying touch sensor 10) by anobject (e.g., a finger, palm, stylus, or other suitable object) andpresence of an object (e.g., a finger, palm, stylus, or other suitableobject) within a detectable range of touch sensor 10 where the objectdoes not necessarily physically contact touch sensor 10 (or a coverlayer overlaying touch sensor 10). For example, a touch or proximityinput refers to an input where an object is in physical contact with thecover panel of a device. Additionally or alternatively, a touch orproximity input refers to detecting an object within a particulardistance (e.g., hovering) over the cover panel (e.g., hovering).

In one embodiment, when touch-sensor controller of device 50 hasdetected active stylus 30 within touch-sensitive area 54, touch-sensorcontroller 12 enters (or remains in) the “object detected” mode. In the“object detected” mode, touch-sensor controller 12 discontinues somemeasurements (e.g., self-capacitance and mutual capacitance) andperforms measurements specific to communicating with active stylus 30.In one embodiment, the “object detected” mode uses a communicationscheme between active stylus 30 and device 50 that includes asynchronization phase and a listen phase. For example, in thesynchronization phase active stylus 30 is synchronized to device 50prior to the communication of other data between active stylus 30 anddevice 50. In one embodiment, this synchronization is performed througha synchronization (“sync”) signal transmitted by the electrodes oftouch-sensitive area 54 to active stylus 30. In certain embodiments, thesynchronization signal comprises a pre-determined bit sequence, e.g., apulse wave. For example, the synchronization signal is a square wave,sine wave, or any suitable voltage waveform.

In one embodiment, in the listen phase, active stylus 30 detects thesynchronization signal and active stylus 30 responds with acommunication signal (e.g., a series of pulses) onto which data isencoded. For example, touch-sensor controller 12 uses sample integratorsconnected to electrodes of touch-sensitive area 54 at pre-determinedtime intervals that correspond to the frequency of the synchronizationsignal. In one embodiment, the synchronization signal initiates,provides for, or terminates the communication signal between activestylus 30 and one or more devices 50 or one or more users.

When the housing of device 50 is in contact with the user, theelectrodes of device 50 are capacitively coupled to the hand that iscontact with device 50. The magnitude of the coupling is determined bythe area and proximity of the user's hand to device 50. An object, suchas a finger or stylus, in proximity to the electrodes definingtouch-sensitive area 54 initiates a transfer of an amount of chargebetween the object and the electrodes of device 50. Given the user isholding the outer body of active stylus 30, which is coupled to a localground of active stylus 30, the user couples a signal (e.g., asynchronization signal) transmitted by device 50 to the local ground ofactive stylus 30. This capacitive coupling reduces or inverts the signalreferenced to the local ground of active stylus 30. For example, if theuser places a large area touch (e.g., through a palm touch) locatedabove the electrodes of touch sensor 10 that receive the applied signal,the applied signal is coupled into the local ground of active stylus 30through the user holding device 50.

As described above, the sense unit of active stylus 30 is capacitivelycoupled to the electrodes of touch sensor 10, such that the sense unitof active stylus 30 receives a differential (e.g., the edges) of theapplied signal transmitted by the electrodes of touch-sensor 10. Theamplitude of the applied signal received by the sense unit of activestylus 30 depends on any suitable combination of the amplitude of theapplied signal, the coupling between the electrodes, and the slew rateof the edges of the applied signal. Furthermore, a large area touchwithin touch-sensitive area 54 of touch sensor 10 creates capacitiveloading on the electrodes of touch sensor 10 that alters the appliedsignal received by active stylus 30. For example, the capacitive loadingfrom a large area touch within touch-sensitive area 54 reduces the slewrate of the edges of the applied signal. In some instances, thecapacitive coupling of the signal through the user is reduced byexcluding electrodes underneath a touch input from receiving the signaland transmitting the signal using the remaining electrodes.

FIGS. 5-8 illustrate an example pattern for applying voltages toelectrodes 24A and 24B of touch sensor 10 to search for an object inaccordance with an embodiment. For example, FIGS. 5-8 illustrate exampleobject detection bias patterns. In the illustrated example, the patternincludes transitioning areas of touch sensor 10 through four states(shown in FIGS. 5-8, respectively); however, it is noted that thepresent technology is not limited to these example patterns.Additionally, although described as a pattern, it is noted that thepresent technology is not limited to these example patterns, and thatother patterns may be implemented.

As described above, touch sensor 10 includes a set of electrodes 24A-Barrayed in a first orientation and another set of electrodes 24A-Barrayed in a second orientation, such that touch-sensitive area 54 oftouch sensor 10 is defined by the two-dimensional array of electrodes24A-B. Electrodes 24A-B are described based on their orientation intouch sensor 10. For example, electrodes oriented along a horizontaldirection (e.g., x-axis) is referred to as x-electrodes and electrodesoriented along a vertical direction (e.g., y-axis) is referred to asy-electrodes. Although this disclosure describes a touch sensorincluding electrodes having particular orientations, it is noted thatthe present technology is not limited to these example orientations, andother orientations may be implemented.

As described above, in the “object not detected” mode, touch-sensorcontroller 12 performs a modified self-capacitance measurement todetermine the position of an object, such as for example an activestylus or a portion of a human hand of the user, within touch-sensitivearea 54 defined by electrodes 24A-B. Touch-sensor controller 12 drives aset 106A of one or more electrodes 24A of touch sensor 10 to transmitthe applied signal, e.g., synchronization signal, to search for anobject (e.g., active stylus 30) in proximity to touch sensor 10. Theposition of active stylus 30 is determined by transmitting asynchronization signal to active stylus 30 and “listening,” such asdescribed herein with reference to a listen phase, for a signaltransmitted by active stylus 30 in response to active stylus 30receiving the synchronization signal. In one embodiment, touch-sensorcontroller 12 applies the synchronization signal to set 106A of one ormore electrodes 24A, and applies a voltage (e.g., a low voltage) to set106B of one or electrodes 24B. For example, the signal applied to set106A of electrodes 24A includes a number of pulses that have anamplitude that corresponds to a pre-determined peak voltage, such as asupply voltage. As another example, the low voltage applied to set 106Bof electrodes 24B is ground or any reference voltage. In one embodiment,reference to a “high” bias refers to applying a signal of any voltageabove the reference voltage to the electrodes, while reference to “low”bias refers to applying a reference voltage (e.g., ground) toelectrodes. Although this disclosure describes techniques for locatingand synchronizing with an active stylus using particular voltage values,it is noted that the present technology is not limited to these exampleembodiments, and other example embodiments may be implemented.

FIG. 5 illustrates an example pattern for applying voltages during afirst time period in accordance with an embodiment. In one embodiment,signals are applied to different areas of touch sensor 10 tosystematically cycle through the touch-sensitive area to determine theposition of the object providing the input to touch sensor 10. Thecontroller of touch sensor 10 selects a set 106A of electrodes 24A toreceive a signal (e.g., a synchronization signal) or a set 106B ofelectrodes 24B to receive a reference voltage, such as, for example, alow voltage (e.g., ground) such that patterns of biased electrodes 24A-Bare formed. For example, these patterns partition touch-sensitive area54 into areas that have a “full” signal, “medium” signal, or are held atthe low voltage.

For example, first signal area 102 include an area with an overlap ofset 106A of electrodes 24A that receive the applied signal. Forinstance, when x-electrodes 24A overlap y-electrodes 24A that bothreceive the applied signal, an area 102 of the overlap has a maximumamplitude or “full” signal. As another example, second signal areas 104is defined as an area with overlap of an electrode 24A receiving theapplied signal with an electrode 24B receiving the low voltage. Forinstance, when y-electrodes 24A overlap x-electrodes 24B or x-electrodes24A overlap y-electrode 24B, the area 104 of the overlap hasapproximately half the applied signal or “medium” signal. Furthermore,low voltage area 112 is defined as an overlap between electrodes 24Bthat receive the low voltage. For example, when y-electrode 24B, whichreceives the low voltage, overlaps x-electrode 24B, which also receivesthe low voltage, area 112 is classified as a third voltage area 112. Inone embodiment, the signal with the peak voltage is applied to set 106Aof electrodes 24A at substantially the same time as the low voltage isapplied to set 106B of electrodes 24B.

In one embodiment, the presence of second signal area 104 and thirdsignal area 112 reduces the amount of or eliminates coupling of theapplied signal through large area touches within touch-sensitive area 54of touch sensor 10 as described above. For example, a large area touchwithin a second signal area 104 couples the applied signal to the senseunit of active stylus 30 from the “medium” signal and a large area touchwithin a third voltage area 112 couples the applied signal to the senseunit of active stylus 30 from the low voltage. In one embodiment, bysystemically cycling through different patterns, portions oftouch-sensitive area 54 systematically receive the “full” signal and lowvoltage during the “object not detected” mode of operation. In oneembodiment, the “low voltage” may include a voltage with a fixed value.For example, if the “full” signal is a square wave with pre-determinedvoltage values of 0 volts and 3 volts, the “low voltage” may be 3 volts,0 volts, or any suitable fixed voltage. In another embodiment, the “lowvoltage” may be replaced with a signal having a reduced amplituderelative to the “full” signal. For example, the “low voltage” isreplaced with a signal that varies between 0 volts to 1 volt relative toa “full” signal that varies between 0 volts to 3 volts.

Touch-sensitive area 54 is partitioned into any combination of one ormore first signal areas 102, one or more second signal areas 104, andone or more third voltage areas 112, as illustrated in the examples ofFIGS. 5-8. In one embodiment, which areas are classified as first signalareas 102 and which areas are classified as second signal areas 104 ischaracterized by which combinations of electrodes 24A that are selectedto receive the applied signal and electrodes 24B that are selected to bebiased to the low voltage (e.g., ground).

In one embodiment, touch-sensor controller 12 selects set 106A ofelectrodes 24A, such that electrodes 24B receiving the low voltage isinterposed between electrodes 24A. Touch-sensor controller 12 modifiesthe set 106A of electrodes 24A that are selected to receive the appliedsignal and set 106B of electrodes 24B selected to receive the lowvoltage as a function of time. In one embodiment, touch-sensorcontroller 12 systematically cycles through patterns that include set106A of electrodes 24A and set 106B of electrodes 24B. For example, set106A of electrodes 24A and set 106B of electrodes 24B during a firsttime period forms a pattern of first signal areas 102, second signalareas 104, and third voltage areas 112 such as, for example, in a manneras illustrated FIG. 5.

FIG. 6 illustrates an example pattern for applying voltages during asecond time period in accordance with an embodiment. Touch-sensorcontroller 12 modifies set 106A of electrodes 24A and set 106B ofelectrodes 24B, such that the pattern of electrodes 24A and electrodes24B during a second time period is offset in the x-direction relativethe pattern during the first time period. In one embodiment,touch-sensor controller 12 modifies set 106A of electrodes 24A and set106B of electrodes 24B, such that the number of electrodes 24A-Bincluded in each set 106A-B varies. For example, in a first cycle ofpatterns, set 106A of electrodes 24A includes bands or subsets of threeelectrodes 24A and in a second cycle, set 106A of electrodes 24Aincludes bands of four electrodes 24A. Although this disclosureillustrates and describes sets of electrodes having bands or subsetswith a particular number of electrodes, it is noted that the presenttechnology is not limited to these example sets of electrodes, and thatother configurations may be implemented, such as for example bands withan equal number of electrodes 24A and electrodes 24B, or bands with adifferent number of electrodes 24A compared to the number of electrodes24B.

FIG. 7 illustrates an example pattern for applying voltages during athird time period in accordance with an embodiment. Touch-sensorcontroller 12 modifies set 106A of electrodes 24A and set 106B ofelectrodes 24B, such that the pattern of selected electrodes 24A andunselected electrodes 24B during a third time period is offset in they-direction relative the pattern during the first time period, such as,for example, in a manner as illustrated FIG. 7. In one embodiment,touch-sensor controller 12 modifies set 106A of selected electrodes 24Aand set 106B of electrodes 24B, such that the position of subsets orbands of electrodes 24A-B varies as a function of time. For example, theoffset of bands of electrodes 24A varies in position by a number ofelectrodes along either the horizontal or vertical orientation (e.g.,extending along a x-axis or y-axis, respectively). The application ofthe signal on electrodes 24A returns position data corresponding to anytouch input within touch-sensitive area 54. For example, the position ofactive stylus 30 is determined by identifying the x-electrodes andy-electrodes detecting the highest amplitude signal received in responseto the signal transmitted by electrodes 24A of touch sensor 10. Thisposition data in turn is used for subsequent “object detected” modemeasurements, such as, for example, in a manner as described below.

FIG. 8 illustrates an example pattern for applying voltages during afourth time period in accordance with an embodiment. Touch-sensorcontroller 12 modifies set 106A of electrodes 24A receiving the appliedsignal and set 106B of electrodes 24B receiving the low voltage, suchthat the pattern of selected electrodes 24A and unselected electrodes24B is offset in the x-direction from the pattern of the third timeperiod. In one embodiment, the offset in the pattern at different timeperiods may correspond to a pre-determined number of unselectedelectrodes 24B. For example, the offset is equal to the number ofunselected electrodes 24B in set 106B. In one embodiment, the patternscycle through a sequene to cover either a majority or the entirety ofthe touch-sensitive area 54 during a pre-determined number of cycles ortime periods, e.g., four cycles. Although this disclosure illustratesand describes a technique of transmitting a signal to an active stylususing a particular number of particular electrode patterns, it is notedthat the present technology is not limited to these example techniques,and that other techniques may be implemented.

FIGS. 9-13 illustrate example touch exclusion bias patterns inaccordance with an embodiment. As described above, the capacitivecoupling of the signal through the user is reduced by excluding a set106B of electrodes 24B underneath an area 110 of a touch input fromreceiving the signal and transmitting the signal using the remainingelectrodes. In the illustrated example, set 106B of electrodes 24Bcovering at least a portion of area 110 of the touch input (shown inFIGS. 9-13) receives the low voltage to reduce coupling between touchsensor 10 and the sense unit of active stylus 30. In one embodiment,touch-sensor controller 12 applies the low voltage to set 106B ofelectrodes 24B corresponding to an area 110 of a touch-input withintouch-sensitive area 54. For example, position data corresponding torelatively large area touches is received from the self-capacitancemeasurements performed as part of the “object not detected” mode. Usingthe position data, touch-sensor controller 12 selects set 106B ofelectrodes 24B corresponding to area 110 of the touch and applies thelow voltage to a set 106B of electrodes 24B. As described above,touch-sensor controller 12 applies a signal to set 106A of electrodes24A and a low voltage on one or electrodes 24B. For example, the signalapplied to electrodes 24A includes a number of pulses that have anamplitude of a pre-determined voltage, such as the supply voltage.

FIG. 9 illustrates an example touch exclusion bias pattern coveringtouch area 110 of a touch input in accordance with an embodiment. In oneembodiment, the self-capacitance measurement data corresponding to thetouch input is processed to determine one or more edges of the toucharea 110. detecting an edge of the area of the touch input, wherein theselected first set of the first plurality of electrodes corresponds tothe detected edge of the touch input To illustrate, an exampleimplementation provides that first and second portions of thex-electrodes and y-electrodes correspond, or overlap, in plan view ofthe touch sensor (as shown) with first portion 900A and second portion900B, respectively, located along the detected edge of the touch area110. In other words, low signal area 112 encompasses the entirety of thetouch area 110 plus a buffer area to compensate for uncertainty in thearea of the touch area 110. Furthermore, set 106B of electrodes 24B thatare selected to receive the low voltage corresponding to an edge of thetouch area 110. As described above, set 106A of electrodes 24A,corresponding to the remaining electrodes, receives the applied signal(e.g., a synchronization signal that includes a pre-determined peakvoltage). Set 106B of electrodes 24B that receives the low voltagedefines a low signal area 112 that encompasses the entirety of touchinput 110, such as, for example, in a manner as illustrated in FIG. 9.For example, low signal area 112 is defined by set 106B of electrodes24B oriented along both the x-direction and y-direction.

FIG. 10 illustrates an example touch exclusion bias pattern covering aportion of touch area 110 of a touch input in accordance with anembodiment. Touch area 110 encompasses a portion of the touch input andexcludes the synchronization signal from a smaller area. Touch-sensorcontroller 12 selects set 106B of electrodes 24B defining a low signalarea 112 that corresponds to a pre-determined percentage of touch area110, e.g., 50 percent, such as, for example, in a manner as illustratedFIG. 10. For example, low signal area 112 includes a center of toucharea 110 or centroid of the touch input, such that low signal area 112is centered about the centroid of touch area 110. In an embodiment, theterm “centroid” is defined as an arithmetic mean position of all pointswithin the touch area 110. Moreover, in one embodiment, a centroid 75 ofthe low signal area 112 substantially corresponds to a location of thecentroid of touch area 110.

FIG. 11 illustrates an example touch exclusion bias pattern withelectrodes along the horizontal orientation in accordance with anembodiment. In one embodiment, touch-sensor controller 12 selects set106B of electrodes 24B along a single axis corresponding to area 110 ofthe touch input to receive the low voltage. For example, set 106Bincludes electrodes 24B that include or intersect touch area 110 of thetouch input that are oriented along the horizontal direction (e.g.,x-axis). In one embodiment, it may be advantageous, to excludeelectrodes 24B oriented along the horizontal direction when touch area110 has a horizontal orientation. Moreover, one embodiment provides thatset 106B excludes electrodes oriented along the horizontal directionthat do not include or intersect touch area 110.

FIG. 12 illustrates an example touch exclusion bias pattern withelectrodes along the vertical orientation in accordance with anembodiment. In one embodiment, touch-sensor controller 12 selects set106B of electrodes 24B along a single axis corresponding to area 110 ofthe touch input to receive the low voltage. For example, set 106Bincludes electrodes 24B that include or intersect touch area 110 thatare oriented along the vertical direction (e.g., y-axis). In oneembodiment, electrodes 24A outside of set 106B of electrodes 24Breceives the applied signal. Furthermore, one embodiment provides thatset 106B excludes electrodes oriented along the vertical direction thatdo not include or intersect touch area 110. In one embodiment, it may beadvantageous, to exclude set 106B of electrodes 24B oriented along thevertical direction when touch area 110 has a vertical orientation.

FIG. 13 illustrates an example touch exclusion bias pattern for multipletouch inputs in accordance with an embodiment. In one embodiment, set106B of electrodes 106B is selected to exclude the touch area 110.Furthermore, selection of a set 106B of electrodes 24B is in response todetermining touch area 110 is larger than a pre-determined thresholdarea, e.g., 20 square millimeters, corresponding to a touch input from apalm of a user. In one embodiment, the pre-determined threshold area,e.g., 10 square millimeters (mm²), corresponds to a touch input from afinger of the user. Furthermore, the pre-determined threshold area is aphysical parameter defined by one or more parameters, e.g., squaremillimeters, percentage of touch-sensitive area 54, number ofelectrodes, number of electrode positions, or any combination thereof.

As described above, touch-sensor controller 12 selects set 106B ofelectrodes 24B corresponding to touch area 110, to receive the lowvoltage. In one embodiment, a touch input located within a second signalarea 104 weakly couples the applied signal to the sense unit of activestylus 30 and a touch input within a low voltage area 112 minimallycouples the applied signal to the sense unit of active stylus 30. In oneembodiment, in situations when a large touch input is present, applyingground to electrodes 24B below area 110 of the touch input reduces oreliminates coupling from touch sensor 10 and the sense unit of activestylus 30 through the user.

FIG. 14A illustrates an example synchronization bias pattern having anoverlap area around a stylus input in accordance with an embodiment. Inthe illustrated example, an overlap of set 106A of electrodes 24Areceiving an applied signal corresponds to an area of touch sensor 10 inwhich a determined position of active stylus 30 is located, whileremaining set 106B of electrodes 24B receive a low voltage. As describedabove, in one embodiment, with respect to stylus interaction,touch-sensor controller 12 operates in at least the following two modes:“object not detected” and “object detected” modes. Based on receiving asignal from active stylus 30 in response to a signal (e.g., asynchronization signal) applied to set 106A of electrodes 24A of touchsensor 10, touch-sensor controller 12 enters the “object detected” mode.For example, in the “object not detected” mode, touch-sensor controller12, during a time interval, transmits a signal (e.g., a synchronizationsignal) to detect an active stylus (e.g., active stylus 30) in proximityto touch sensor 10. In certain embodiments, touch-sensor controller 12transmits the signal (e.g., the synchronization signal) using a sequenceof electrode patterns, such as the electrode pattern described abovewith reference to FIGS. 5-8. In certain embodiments, a signal includinga waveform with one or more peak voltages is applied to set 106A ofelectrodes 24A, while a reference voltage is applied to set 106B ofelectrodes 24B. For example, the signal applied to set 106A ofelectrodes 24A is waveform that has a peak voltage approximately equalto a supply voltage of touch sensor 10 and voltage applied to set 106Bof electrodes 24B is ground. Additionally or alternatively, in the“object not detected” mode, touch-sensor controller 12 transmits asignal to active stylus 30 using a set 106A of electrodes 24A thatexclude an area of a touch input determined using the self-capacitancemeasurements, such as according to the example described above withreference to FIGS. 9-13.

Active stylus 30, when in proximity to touch sensor 10, transmits asignal in response to the synchronization signal transmitted by touchsensor 10. The response signal communicated by active stylus 30 isreceived by set 106A of electrodes 24A of touch sensor 10. Touch-sensorcontroller 12 processes the received signal to determine a position 114of active stylus 30. For example, touch-sensor controller 12 determinesthat active stylus 30 is located in proximity to touch sensor 10 atposition 114 based on identifying one or more x-electrodes andy-electrodes receiving the largest amplitude signal from active stylus30. Although a particular technique for determining position isdescribed, the present disclosure contemplates touch-sensor controller12 determining the position of active stylus 30 according to anysuitable technique.

In one embodiment, touch-sensor controller 12 uses the determinedposition (e.g., position 114) of active stylus 30 to determine theelectrodes 24A to be driven in one or more subsequent detection cyclesto track the position of active stylus 30. For example, touch sensorcontroller 12 may use the determined position (e.g., position 114) ofactive stylus 30 to select set 106A of electrodes 24A that define ashape or area 102 around the determined position 114 of active stylus30, such as, for example, in a manner as illustrated FIGS. 14A-B. In oneembodiment, the signal is applied based at least in part on the area ofthe touch input being larger than a pre-determined area. For example,area 102 is defined as an overlap of set 106A of electrodes 24A thatreceive the applied signal from touch-sensor controller 12. In certainembodiments, the shape of the overlap area 102 of set 106A of electrodes24A is a box formed around the determined position 114 of active stylus30. Although this disclosure describes or illustrates driving or biasingelectrodes such that the overlap of biased electrodes set 1096A of 24Ahas a particular shape, it is noted that the present technology is notlimited to these example shapes, and that other shapes may beimplemented, such as for example a square or rectangular shaped area.

In one embodiment, the overlap of electrodes 24A defines area 102 thatreceives a signal in the next stylus acquisition. As described above,the signal includes one or more pulses having a pre-determined peakvoltage. Electrodes 24B located outside area 102 is selected to receivea pre-determined lower voltage, such as ground or another suitablereference voltage. For example, the determined position 114 of activestylus 30 is determined from measurement data obtained using anytechnique, such as for example, by excluding electrodes 24B in an area110 corresponding to a touch input from transmitting the synchronizationsignal or transmitting the synchronization signal through a cyclicalpattern of electrodes 24A. Although this disclosure describes orillustrates particular techniques of determining the position of activestylus 30, it is noted that the present technology is not limited tothese example techniques, and that other techniques may be implemented,such as for example, through application of the signal to all electrodesof touch sensor 10 and detecting a subsequent response signal fromactive stylus 30.

A majority of touch-sensitive area 54 may receive the low voltage, suchthat the applied signal is not coupled to the sense unit of activestylus 30 through capacitive coupling with the user contacting device50. In one embodiment, the signal that includes the pre-determined peakvoltage is applied to electrodes 24A substantially simultaneously whileapplying the low voltage to electrodes 24B. In one embodiment, a touchinput located within a medium signal area 104 weakly couples the appliedsignal to the sense unit of active stylus 30 and a touch input within alow voltage area minimally couples the applied signal to the sense unitof active stylus 30. As active stylus 30 is being used, the determinedposition 114 of active stylus 30 may move out of area 102. In oneembodiment, selection of set 106A of electrodes 24A receiving theapplied signal is recalculated after every measurement cycle with anupdated determined active stylus position 114. For example, thevelocity, e.g., speed and direction of motion, of active stylus 30 isdetermined based on a change in the determined active stylus position114 obtained from separate measurements and the selection of electrodes24A to receive the signal is adjusted according to the determinedvelocity of active stylus 30.

FIG. 14B illustrates an example synchronization bias pattern having anoverlap and guard band around a stylus input in accordance with anembodiment. In the illustrated example, an overlap of electrodes 24Areceiving an applied signal corresponds to an area of touch sensor 10 inwhich a determined position of active stylus 30 is located, while afirst subset of electrodes 24B receive a low voltage and a second subsetof electrodes 24C receive an inverted signal relative to the signalapplied to electrodes 24A. In one embodiment, the low voltage is groundand the inverted signal applied to electrodes 24C is an inverted versionof the signal applied to electrodes 24A (e.g., 180° out of phase with orhaving a polarity reversed relative to the applied signal).

As described above, in one embodiment, with respect to stylusinteraction, touch-sensor controller 12 may operate in at least thefollowing two modes: “stylus not detected” and “stylus detected” modes.Based on receiving a signal from active stylus 30 in response to asignal (e.g., a synchronization signal) applied to the set of electrodes24A of touch sensor 10, touch-sensor controller 12 enters the “objectdetected” mode. For example, in the “stylus not detected” mode,touch-sensor controller 12, at any suitable interval, transmits a signal(e.g., a synchronization signal) to detect an active stylus (e.g.,active stylus 30) in proximity to touch sensor 10. In one embodiment,touch-sensor controller 12 transmits the signal (e.g., thesynchronization signal) using a sequence of electrode patterns, such asthe electrode pattern described above with reference to FIGS. 5-8.Additionally or alternatively, in the “object not detected” mode,touch-sensor controller 12 transmits a signal to active stylus 30 usinga set 106A of electrodes 24A that exclude an area of a touch inputdetermined using the self-capacitance measurements, such as according tothe example described above with reference to FIGS. 9-13.

Active stylus 30, when in proximity to touch sensor 10, transmits asignal in response to the signal (e.g., the synchronization signal)transmitted by touch sensor 10. The response signal communicated byactive stylus 30 is received by set 106A of electrodes 24A of touchsensor 10. Touch-sensor controller 12 may process the received signal todetermine a position 114 of active stylus 30. For example, touch-sensorcontroller 12 determines that active stylus 30 is located in proximityto touch sensor 10 at position 114 based on identifying one or morex-electrodes and y-electrodes receiving the largest amplitude signalfrom active stylus 30. Although a particular technique for determiningposition is described, it is noted that the present technology is notlimited to these example techniques, and that other techniques may beimplemented.

In one embodiment, touch-sensor controller 12 uses the determinedposition (e.g., position 114) of an object (e.g., active stylus 30) todetermine the electrodes 24A to be driven in one or more subsequentdetection cycles to track the position of active stylus 30. For example,touch sensor controller 12 uses the determined position (e.g., position114) of active stylus 30 to select set 106A of electrodes 24A thatdefine a shape or area 102 around the determined position 114 of activestylus 30, such as, for example, in a manner as illustrated FIG. 14A.For example, area 102 is defined as an overlap of electrodes 24A thatreceive the applied signal from touch-sensor controller 12. In oneembodiment, the shape of the overlap area 102 of electrodes 24A is a boxformed around the determined position 114 of active stylus 30. Althoughthis disclosure describes or illustrates driving or biasing electrodessuch that the overlap of biased electrodes 24A has a particular shape,it is noted that the present technology is not limited to these exampleshapes, and that other shapes may be implemented, such as for example asquare or rectangular shaped area.

In one embodiment, the overlap of electrodes 24A defines area 102 thatreceives a signal in the next object acquisition. As described above,the signal includes one or more pulses having a pre-determined peakvoltage. Set 106C of electrodes 24C located outside area 102 is selectedto receive the inverted signal and electrodes 24B adjacent to area 102is selected to receive a pre-determined lower voltage, such as ground oranother suitable reference voltage. For example, the determined position114 of active stylus 30 is determined from measurement data obtainedusing any suitable technique, such as for example, by excludingelectrodes 24B in an area 110 corresponding to a touch input fromtransmitting the synchronization signal or transmitting thesynchronization signal through a cyclical pattern of electrodes 24A.Although this disclosure describes or illustrates particular techniquesof determining the position of active stylus 30, it is noted that thepresent technology is not limited to these example techniques, and thatother techniques may be implemented, such as for example, throughapplication of the signal to all electrodes of touch sensor 10 anddetecting a subsequent response signal from active stylus 30.

A majority of the touch-sensitive area may receive the inverted signal,such that the inverted signal is coupled to the sense unit of activestylus 30 through capacitive coupling with the user contacting device50. The coupling of the inverted signal to the sense unit of activestylus 30 through the user increases the magnitude of the applied signaldetected by the edge detectors of the sense unit. Furthermore, applyingthe low voltage to electrodes 24B adjacent to area 102 causes electrodes24B to act as a guard band, thereby preventing the inverted signal fromcorrupting the applied signal of electrodes 24A detected by the senseunit of active stylus 30. In one embodiment, the signal that includesthe pre-determined peak voltage is applied to electrodes 24Asubstantially simultaneously while applying the low voltage toelectrodes 24B and the inverted signal to set 106C of electrodes 24C.For example, the inverted signal is applied to electrodes 24C in areasthat includes a touch input or substantially the touch sensitive area ofthe touch sensor excluding area 102 and the guard band adjacent to area102. As active stylus 30 is being used, the determined position 114 ofactive stylus 30 moves out of area 102. In one embodiment, selection ofthe set of electrodes 24A receiving the applied signal and the subset ofelectrodes 24B receiving the low voltage is recalculated after everymeasurement cycle with an updated determined active stylus position 114.For example, the velocity, e.g., speed and direction of motion, ofactive stylus 30 is determined based on a change in the determinedactive stylus position 114 obtained from separate measurements and theselection of electrodes 24A and 24B to receive the applied signal andlow voltage, respectively, is adjusted according to the determinedvelocity of active stylus 30.

FIG. 15 illustrates an example synchronization bias pattern having oneor more overlap areas along one or more edges of the touch sensor inaccordance with an embodiment. In the illustrated example, touch-sensorcontroller 12 selects a set 106A of electrodes 24A along one or moreedges of touch sensor 10, while remaining set 106B of electrodes 24Breceive a low voltage. In one embodiment, when the determined position114 of active stylus 30 is in proximity to an edge or corner oftouch-sensitive area 54, the area encompassing determined position 114of active stylus 30 may provide inadequate coverage to account for theapproximation of determined position 114 of active stylus 30 andpossible movement of active stylus 30 during use. Herein, reference toan edge encompasses an outermost electrode of the touch-sensitive areaand a pre-determined number of electrodes adjacent to the outermostelectrode. Furthermore, reference to an interior area encompasses thecenter of the touch-sensitive area up to a pre-determined number ofelectrodes away from the center of the touch-sensitive area. In oneembodiment, set 106A of one or more electrodes 24A that correspond to anedge of touch-sensitive area 54 is selected to receive the appliedsignal, while set 106B of electrodes 24B within the interior area oftouch-sensitive area 54 may receive the low voltage. Furthermore, areas102 defined by an overlap of set 106A of electrodes 24A andcorresponding to the corners of touch-sensitive area 54 transmits the“full” signal, while areas 104 defined by an overlap of set 106A ofelectrodes 24A and set 106B of electrodes 24B along the edges transmitsa “medium” signal.

Touch inputs within the interior area of touch-sensitive area 54, e.g.,outside of areas 102 or area 104, are coupled to ground of device 50through set 106B of electrodes 24B. In one embodiment, touch-sensorcontroller 12 selects sets 106A of electrodes 24A corresponding to anyedge of the periphery of touch-sensitive area 54 to receive the appliedsignal. For example, touch-sensor controller 12 selects sets 106A ofthree electrodes 24A that correspond to the entire periphery oftouch-sensitive area 54. As another example, touch-sensor controller 12selects one or more sets 106A of three electrodes 24A including theoutermost electrode along two edges closest to the determined position114 of active stylus 30. Although this disclosure describes orillustrates particular techniques for determining the position 114 ofactive stylus 30, it is noted that the present technology is not limitedto these example techniques, and that other techniques may beimplemented, such as for example applying the signal to all electrodesof the touch-sensor and detecting a subsequent response signal fromactive stylus 30.

In one embodiment, touch-sensor controller 12 selects a new set 106A ofelectrodes 24A to receive the applied signal from defining an area 102around the determined position 114 of active stylus 30 to set 106A ofelectrodes 24A that includes one or more edges of touch sensor 10, suchas, for example, in a manner as illustrated FIG. 15. For example, whenthe determined position 114A of active stylus 30 is within the interiorarea of touch-sensitive area 54, set 106A of electrodes 24Acorresponding to area 102 encompassing determined position 114A isselected, such as, for example, in a manner as illustrated FIG. 14A.Furthermore, when the determined position 114B moves within apre-determined distance from an outermost electrode along the edge oftouch-sensitive area 54, set 106A of electrodes 24A corresponding to oneor more edges of touch sensor 10 are selected to receive the appliedsignal, such as, for example, in a manner as illustrated FIG. 15. In oneembodiment, set 106A of electrodes 24A includes a pre-determined (e.g.,4 electrodes) number of contiguous electrodes 24A that includes theoutermost electrode along each edge of touch sensor 10. Thepre-determined distance is a fixed distance from the outermost electrodealong the edge of touch sensor 10 (e.g., five millimeters), apre-determined percentage of touch-sensitive area 54 (e.g., fourpercent), a pre-determined number of contiguous electrodes,pre-determined electrode positions, or any combination thereof.

One or more of the “object not detected” mode measurements is used inconjunction with one or more of the “object detected” mode measurementsdescribed above. For example, touch-sensor controller 12 transmits asynchronization signal to an active stylus. As described above, thesense unit of active stylus 30 receives the synchronization signal andthe drive unit of active stylus 30 sends a signal to a device inresponse to the received synchronization signal. Touch-sensor controller12 enters the “object detected” mode based on receiving the signaltransmitted by active stylus 30. In one embodiment, touch-sensorcontroller 12 discontinues performing self-capacitance or mutualcapacitance measurements and selects set 106A of electrodes 24A thatdefine an area encompassing a determined position 114 of active stylus30, such as, for example, in a manner as illustrated FIG. 14A. Inaddition, the touch-senor controller 12 determines a velocity ofmovement of active stylus 30 and dynamically adjusts set 106A ofselected electrodes 24A to encompass the movement of active stylus 30.

In one embodiment, touch-sensor controller 12 determines an area 110 ofan input of active stylus 30 through measurement data, e.g., from aself-capacitance measurement, and exclude set 106B of electrodes 24Bthat define an area 112 that encompasses area 110 of the input of activestylus 30 from transmitting a subsequent synchronization signal, suchas, for example, in a manner as illustrated FIGS. 9-13. As describedabove, the drive unit of active stylus 30 sends a signal to a device inresponse to the received synchronization signal and the controller oftouch sensor 10 switches to the “object detected” mode in response toreceiving the signal transmitted by active stylus 30. In one embodiment,touch-sensor controller 12 discontinues performing self-capacitance ormutual capacitance measurements and select sets 106A of electrodes 24Aalong one or more edges of the periphery of touch-sensitive area 54 inresponse to determining the determined position 114 of active stylus 30is within a pre-determined distance from the periphery, such as, forexample, in a manner as illustrated FIG. 15. As described above,touch-senor controller 12 determines a velocity of movement of activestylus 30 and dynamically adjusts set 106A of selected electrodes 24A toencompass the movement of active stylus 30. For example, touch-sensorcontroller 12 dynamically adjusts set 106A of electrodes 24A from one ormore sets 106A of electrodes 24A along the edges of the periphery to set106A of electrodes 24A located in the interior area of touch-sensitivearea 54 in response to determining the position 114 of active stylus 30moving from within a pre-determined distance from the edge to withoutthe pre-determined distance from an edge.

In certain embodiments, referencing a majority of electrodes 24B oftouch sensor 10 to a reference voltage (e.g., ground) reduces oreliminates coupling between touch inputs on touch sensor 10 and thesense unit of active stylus 30. In certain embodiments, synchronizationof active stylus 30 to device 50 is facilitated while active stylus 30is near the edges or corners of touch sensor 10 by selecting electrodes24A along one or more edges or the entire periphery of touch sensor 10.

FIG. 16A illustrates an example method for detecting an object inaccordance with an embodiment. The method 1600 starts at step 1610,where a position of an object is determined. In one embodiment, thetouch-sensor controller performs a modified self-capacitance measurementto determine the position of an object. In another embodiment, aposition of a stylus is determined by transmitting a synchronizationsignal to the stylus and “listening” for a signal transmitted by thestylus in response to the synchronization signal. In the absence of anobject, the touch-sensor controller continues to operate in the “objectnot detected” mode. At step 1620 an area around the determined positionof the object is determined. For example, the touch-sensor controllerdetermines whether the object is located at the edge or within theinterior of the touch-sensitive area. In one embodiment, thetouch-sensor controller selects electrodes in a box around the area ofthe object. At step 1630, the area around the object is scanned todetermine whether the object has moved to a new position relative to thetouch sensor. In one embodiment, a velocity (e.g., speed and directionof motion) of the object is determined based on a change in thedetermined object position obtained from separate measurements. In oneembodiment, if the object has moved to a new position relative to thetouch sensor, the touch-sensor controller determines whether the objectis near the edge or interior as illustrated in step 1620. Otherwise, thetouch-sensor controller goes into the “object not detected” mode anddetermines the position of the object as illustrated in step 1610.Although this disclosure describes and illustrates particular steps ofthe method of FIG. 16A as occurring in a particular order, it is notedthat the present technology is not limited to these example steps. Oneembodiment may repeat one or more steps of the method of FIG. 16A.Moreover, although this disclosure describes and illustrates an examplemethod for detecting an object including the particular steps of themethod of FIG. 16A, it is noted that the present technology is notlimited to these example steps, and that other methods may beimplemented, which may include all, some, or none of the steps of themethod of FIG. 16A. Moreover, although this disclosure describes andillustrates particular components carrying out particular steps of themethod of FIG. 16A, it is noted that the present technology is notlimited to these example components, and that other configurations ofcomponents may be implemented.

FIG. 16B illustrates an example method for detecting an object throughsearch patterns in accordance with an embodiment. The method 1650 startsat step 1660, where a set of first electrodes (e.g., electrodes alongthe horizontal orientation) and a set of the second electrodes (e.g.,electrodes along the vertical orientation) are selected. In oneembodiment, the selected electrodes include an overlap area formed bythe selected first and second electrodes. At step 1670 a signal thatincludes a first pre-determined voltage is applied to the selectedelectrodes at a first time period. For example, the signal that includesa first pre-determined voltage is a series of pulses each with a peakvoltage of a supply voltage. In one embodiment, a state of the overlaparea in the first time period corresponds to a high signal. At step1680, the first pre-determined voltage is simultaneously applied to theselected first electrodes and a second pre-determined voltage issimultaneously applied to the selected second electrodes at a secondtime period. For example, the second pre-determined voltage is a groundof a device. In one embodiment, the state of the overlap areacorresponds to a medium signal during the second time period. Step 1690simultaneously applies the second pre-determined voltage to the selectedelectrodes at a third time period, at which point the method ends. Inone embodiment, the state of the overlap area corresponds to a lowsignal during the third time period. Although this disclosure describesand illustrates particular steps of the method of FIG. 16B as occurringin a particular order, it is noted that the present technology is notlimited to these example steps. One embodiment may repeat one or moresteps of the method of FIG. 16B. Moreover, although this disclosuredescribes and illustrates an example method for detecting a stylusincluding the particular steps of the method of FIG. 16B, it is notedthat the present technology is not limited to these example steps, andthat other methods may be implemented, which may include all, some, ornone of the steps of the method of FIG. 16B. Moreover, although thisdisclosure describes and illustrates particular components carrying outparticular steps of the method of FIG. 16B, it is noted that the presenttechnology is not limited to these example components, and that otherconfigurations of components may be implemented.

FIG. 17 illustrates an example method for detecting an object throughtouch area exclusion in accordance with an embodiment. The method 1700starts at step 1710, by determining a position of a touch input in atouch-sensitive area of a touch sensor. In one embodiment, the touchinput has an area larger than a pre-determined area. Step 1720 selects aset of first electrodes covering at least a portion of the area of thetouch input. For example, the selected electrodes may have a verticalorientation. At step 1730, the first pre-determined voltage issimultaneously applied to the selected first electrodes. For example,the first pre-determined voltage is a series of pulse with a peakvoltage of a supply voltage. Step 1740 simultaneously applies a secondpre-determined voltage to electrodes other than the selected electrodes,at which point the method ends. For example, the second pre-determinedvoltage is ground of a device. In one embodiment, the secondpre-determined voltage is applied while the first pre-determined voltageis being applied. Although this disclosure describes and illustratesparticular steps of the method of FIG. 17 as occurring in a particularorder, it is noted that the present technology is not limited to theseexample steps. One embodiment may repeat one or more steps of the methodof FIG. 17. Moreover, although this disclosure describes and illustratesan example method for detecting a stylus including the particular stepsof the method of FIG. 17, it is noted that the present technology is notlimited to these example steps, and that other methods may beimplemented, which may include all, some, or none of the steps of themethod of FIG. 17. Moreover, although this disclosure describes andillustrates particular components carrying out particular steps of themethod of FIG. 17, it is noted that the present technology is notlimited to these example components, and that other configurations ofcomponents may be implemented.

FIG. 18 illustrates an example method for synchronizing a stylus with adevice in accordance with an embodiment. The method 1800 starts at step1810, where a position of a stylus on a touch sensor is determined. Step1820 selects a first set of first electrodes (e.g., electrodes along thehorizontal orientation) and a first set of the second electrodes (e.g.,electrodes along the vertical orientation) are selected. In oneembodiment, the selected electrodes include an overlap area formed bythe selected first and second electrodes and corresponding to an area ofthe touch sensor in which the determined position is a location of thestylus. At step 1830, a first pre-determined voltage is simultaneouslyapplied to the first set of electrodes. For example, the firstpre-determined voltage is a series of pulse with a peak voltage of asupply voltage. Step 1840 simultaneously applies a second pre-determinedvoltage to a second set of first electrodes and a second set of secondelectrodes, at which point the method ends. For example, the secondpre-determined voltage is ground of a device. In one embodiment, thesecond pre-determined voltage is applied while the first pre-determinedvoltage is being applied. Although this disclosure describes andillustrates particular steps of the method of FIG. 18 as occurring in aparticular order, it is noted that the present technology is not limitedto these example steps. One embodiment may repeat one or more steps ofthe method of FIG. 18. Moreover, although this disclosure describes andillustrates an example method for synchronizing a stylus including theparticular steps of the method of FIG. 18, it is noted that the presenttechnology is not limited to these example steps, and that other methodsmay be implemented, which may include all, some, or none of the steps ofthe method of FIG. 18. Moreover, although this disclosure describes andillustrates particular components carrying out particular steps of themethod of FIG. 18, it is noted that the present technology is notlimited to these example components, and that other configurations ofcomponents may be implemented.

Herein, a computer-readable non-transitory storage medium or mediaincludes one or more semiconductor-based or other integrated circuits(ICs) (such, as for example, field-programmable gate arrays (FPGAs) orapplication-specific ICs (ASICs)), hard disk drives (HDDs), hybrid harddrives (HHDs), optical discs, optical disc drives (ODDs),magneto-optical discs, magneto-optical drives, floppy diskettes, floppydisk drives (FDDs), magnetic tapes, solid-state drives (SSDs),RAM-drives, SECURE DIGITAL cards or drives, any other computer-readablenon-transitory storage media, or any combination of two or more ofthese. A computer-readable non-transitory storage medium is volatile,non-volatile, or a combination of volatile and non-volatile.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Similarly, theappended claims encompass all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. A method comprising: selecting, for a touchsensor comprising a first plurality of electrodes and a second pluralityof electrodes, a first set of the first plurality of electrodes and asecond set of the second plurality of electrodes, the first plurality ofelectrodes having a first orientation and the second plurality ofelectrodes having a second orientation, the second orientation beingdifferent from the first orientation, an overlap area being formed by anoverlap of the first set and second set; applying, during a first timeperiod, a signal comprising a first pre-determined voltage to the firstset and the second set such that, during the first time period, theoverlap area has a first signal state; applying, during a second timeperiod, the signal to the first set and a second pre-determined voltageto the second set such that, during the second time period, the overlaparea has a second signal state; and applying, during a third timeperiod, the second pre-determined voltage to the first set and thesecond set such that, during the third time period, the overlap area hasa third signal state.
 2. The method of claim 1, further comprisingapplying, during a fourth time period, the signal to the second set andthe second pre-determined voltage to the first set such that, during thefourth time period, the overlap area has the second signal state.
 3. Themethod of claim 1, further comprising performing one or more of thefollowing: modifying a quantity of electrodes included in the first setsuch that a width of the first set is changed in response to determiningan absence of a touch input; and modifying a quantity of electrodesincluded in the second set such that a width of the second set ischanged in response to determining an absence of a touch input.
 4. Themethod of claim 1, further comprising: removing one of the electrodesfrom the first set of in response to determining an absence of a touchinput; selecting an electrode from among the first set based on theelectrode being positioned adjacent to the selected set of the firstplurality of electrodes; and adding the first electrode to the firstset, such that a location of the first set is offset at least in partalong the second orientation.
 5. The method of claim 1, wherein thesignal comprises one or more pulses comprising the first pre-determinedvoltage.
 6. The method of claim 1, further comprising applying, duringthe first time period, the second pre-determined voltage to theelectrodes of the first plurality of electrodes other than the first setand the electrodes of the second plurality of electrodes other than thesecond set, wherein the first pre-determined voltage is higher than thesecond pre-determined voltage.
 7. The method of claim 1, wherein thesecond pre-determined voltage is ground.
 8. A controller comprising: aprocessor; and a memory coupled to the processor, the memory storinglogic configured to cause the processor as a result of being by executedthe processor, to: select, for a touch sensor comprising a firstplurality of electrodes and a second plurality of electrodes, a firstset of the first plurality of electrodes and a second set of the secondplurality of electrodes, the first plurality of electrodes having afirst orientation and the second plurality of electrodes having a secondorientation, the second orientation being different from the firstorientation, an overlap area being formed by an overlap of the first setand second set; apply, during a first time period, a signal comprising afirst pre-determined voltage to the first set and the second set suchthat, during the first time period, the overlap area has a first signalstate; apply, during a second time period, the signal to the first setand a second pre-determined voltage to the second set such that, duringthe second time period, the overlap area has a second signal state; andapply, during a third time period, the second pre-determined voltage tothe first set and the second set such that, during the third timeperiod, the overlap area has a third signal state.
 9. The controller ofclaim 8, wherein the processor is further configured to apply, during afourth time period, the signal to the second set and the secondpre-determined voltage to the first set such that, during the fourthtime period, the overlap area has the second signal state.
 10. Thecontroller of claim 8, wherein the processor is further configured toperform one or more of the following: modify a quantity of electrodesincluded in the first set such that a width of the first set is changedin response to determining an absence of a touch input; and modify aquantity of electrodes included in the second set such that a width ofthe second set is changed in response to determining an absence of atouch input.
 11. The controller of claim 8, wherein the processor isfurther configured to: remove one of the electrodes from the first setof in response to determining an absence of a touch input; select anelectrode from among the first set based on the electrode beingpositioned adjacent to the selected set of the first plurality ofelectrodes; and add the first electrode to the first set, such that alocation of the first set is offset at least in part along the secondorientation.
 12. The controller of claim 8, wherein the signal comprisesone or more pulses comprising the first pre-determined voltage.
 13. Thecontroller of claim 8, wherein the processor is further configured toapply, during the first time period, the second pre-determined voltageto the electrodes of the first plurality of electrodes other than thefirst set and the electrodes of the second plurality of electrodes otherthan the second set, wherein the first pre-determined voltage is higherthan the second pre-determined voltage.
 14. The controller of claim 8,wherein the second pre-determined voltage is ground.
 15. A systemcomprising: a touch sensor comprising a first plurality of electrodesand a second plurality of electrodes, a first set of the first pluralityof electrodes and a first set of the second plurality of electrodes, thefirst plurality of electrodes having a first orientation and the secondplurality of electrodes having a second orientation, the secondorientation being different from the first orientation; and a controllercoupled to the touch sensor and embodying logic that is configured whenexecuted to: select, a first set of the first plurality of electrodesand a second set of the second plurality of electrodes, an overlap areabeing formed by an overlap of the first set and second set; apply,during a first time period, a signal comprising a first pre-determinedvoltage to the first set and the second set such that, during the firsttime period, the overlap area has a first signal state; apply, during asecond time period, the signal to the first set and a secondpre-determined voltage to the second set such that, during the secondtime period, the overlap area has a second signal state; and apply,during a third time period, the second pre-determined voltage to thefirst set and the second set such that, during the third time period,the overlap area has a third signal state.
 16. The system of claim 15,wherein the processor is further configured to apply, during a fourthtime period, the signal to the second set and the second pre-determinedvoltage to the first set such that, during the fourth time period, theoverlap area has the second signal state.
 17. The system of claim 15,wherein the processor is further configured to perform one or more ofthe following: modify a quantity of electrodes included in the first setsuch that a width of the first set is changed in response to determiningan absence of a touch input; and modify a quantity of electrodesincluded in the second set such that a width of the second set ischanged in response to determining an absence of a touch input.
 18. Thesystem of claim 15, wherein the processor is further configured to:remove one of the electrodes from the first set of in response todetermining an absence of a touch input; select an electrode from amongthe first set based on the electrode being positioned adjacent to theselected set of the first plurality of electrodes; and add the firstelectrode to the first set, such that a location of the first set isoffset at least in part along the second orientation.
 19. The system ofclaim 15, wherein the signal comprises one or more pulses comprising thefirst pre-determined voltage.
 20. The system of claim 15, wherein theprocessor is further configured to apply, during the first time period,the second pre-determined voltage to the electrodes of the firstplurality of electrodes other than the first set and the electrodes ofthe second plurality of electrodes other than the second set, whereinthe first pre-determined voltage is higher than the secondpre-determined voltage.